Electric amplifier system.



H. C. EGERTON.

{LECTRIC AMPLIFIER SYSTEM, APPLICATION FILED NOV. 15, 1915.

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HENRY C. EGERTON, OF PASSAIC, NEW JERSEY, ASSIGNOR, BY MESNEASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OFNEW YORK.

ELECTRIC AMPLIFIER SYSTEM.

Specification of Letters Patent.

Patented July 10, 191?.

Application filed November 15, 1915. Serial No. 61,550.

To all whom it may] concern:

Be it known that I, HENRY CLIFFORD EonRroN, a citizen of the UnitedStates, residing at Passaic, in the county of Passaic and State of NewJersey, have invented certain new and useful Improvements in ElectricAmplifier Systems, of which the following is a full, clear, concise, andexact description.

This invention relates to amplifier systems for electric currents, andmore particularly to amplifier systems for increasing the intensity oftelephone currents.

The object of this invention is to simplify the arrangement of circuitconnections to permit all of the devices at one station, or all of'thedevices at a plurality of stations on a telephone system of thischaracter, to be supplied with current from one and the same source.

In accordance with this invention, a common source of current supply isprovided with a derived circuit, whereby a transmitter element operatedby an electromagnetically-actuated amplifier means may be supplied withcurrent at a potential lower than the potential of the current suppliedto a primary transmitter. A switching means also provides that thetransmitter element may be included with different sections of thesource of current supply.

This invention is illustrated diagrammatically in the accompanyingdrawing, in which a single telephone station completely equipped inaccordance with this invention is shown.

Referring to the drawing, this invention provides that a plurality ofstations, equipped in a manner similar to that illustrated in thedrawing, may be connected with two main line conductors 1 and 2 in sucha manner that a message transmitted from either one of the stations willbe reproduced in unison at each one of the several stations, includingthe station which may be transmitting the message.

The operation of this system may be described by tracing the processesand circuit action taking place when a message is trans-,'

mitted from the station shown. A switching key 7 is first depressed,thereby including a secondary winding 8 of an induction coil in bridgeon the line conductors 1 and 2. A second circuit also completed by thiskey includ s a t an mitter 9 in e ie ith a p imary winding 10 of theinduction coil on a battery 5. The operating windings l3 and 14 of anelectromagnetically-operated ampllfier motor 12 established in bridge onthe llne conductors 1 and 2 are responsive to current action set up bythe primary transmitter 9, and a transmitter element 15 responds to thearmature movement of this amplifier motor. The transmitter element 15 inturn sets up current action in the primary winding 16 of a secondinduction coil, which is therewith included in series over a derivedcircuit conductor 4 on the left-hand portion of the battery 5. The frameand armature of the electromagnet 12 form a path to complete the circuitfrom the conductor 4 to the transmitter element 15. A telephone receiver18 included in series with the secondary winding of the last-mentionedinduction coil accordingly reproduces in an intensified manner a messagespoken into the transmitter 9, and in like manner the message is alsoreproduced at all stations which maybe connected with the lineconductors 1 and 2.

In order to secure the necessary sensitive-- ness in the electromagnet12, it is provided with each core; therefore a given impulse ofcurrentthrough the operating windings 13 and 14 acts to increase themagnetic pull at one end of the armature while decreasing the magneticpull at the-other end of the armature all in a well-known manner.Suitable bearings at the middle pole piece of the amplifierelectromagnet 12 permit the armature of this magnet to move reciprocallyin a rocking manner in unison with reversals or changes in amplitude ofthe telephone current through the coils 13 and 14,'thereby varying thepressure on the active material of the transmitter element 15.

A switch 21 provides that the transmitter element 15 and the magnetizingcoils 19 and 20 may from time to time be switched to either theleft-hand or the right-hand portion of the battery 5, in order that thecurrent drain may be equalized throughout the battery.

The battery 5 may be employed as a common current source for a pluralityof stations included in a system, or an individual battery may befurnished for each station.

Although a battery has for convenience been shown as the source ofcurrent for this system, it will be understood that any suitablearrangement of generators capable of supplying current at three or morediflerent potentials may be substituted therefor.

It will be further understood that the switching arrangement 21 forcontrolling the derived circuits of the battery may be adapted toseparate the circuits of the secondary transmitter 15 from the circuitsof the magnetizing coils 19 and 20, and that these separated circuitsmay at the same time be included on different portions of the battery 5.

What is claimed is: In a telephone amplifier system, a primarytransmitter, an electromagnetic means controlled by said transmitter, atransmitter element controlled by said electromagnetic means, a commonsource of current supply for said system, means included in derivedrelation with said source of current adapted to supply current to saidtransmitter element at a potential less than the potential of the sourceof supply, and means for obtaining current at said reduced potentialfrom different portions of said common source of current supply.

In Witness whereof, I hereunto subscribemy name this eighth day ofNovember A. D., 1915.

HENRY C. EGERTON.

